Heavy goods vehicle with an overload security device

ABSTRACT

The invention relates to a heavy goods vehicle, specially for the transportation of slag, comprising a loading platform for vessels containing slag, fitted with a gripper device for receiving and moving a standardized load-bearing implement which can be actuated by a hydraulic cylinder ( 11 ) and an anti-tilt device ( 15 ) for the vehicle which operates during movement of said load-bearing implement. The vehicle is also fitted with at least one hydraulic cylinder ( 11 ) with switches. Upon a given stroke of the piston, at least one switch engages a device detecting hydraulic pressure inside the cylinder on one or both sides of the piston. The pressure detection device triggers a security device, e.g. a display for the driver or an operation blocking device.

DESCRIPTION

[0001] The invention is directed to a heavy-duty vehicle with a grippingdevice for picking up and moving a standardized load carrier which canbe actuated by hydraulic cylinders and tipping-prevention means for thevehicle which are in operation during the movement of the load carrier.

[0002] A vehicle of the generic type is known from DE 36 05 665 C2. Itis used for lifting, transporting and tipping a slag vessel, or thelike, provided with side trunnions and is outfitted with a self-driventraction machine and a load transport part provided with wheels, whereina swiveling frame serving to grip the trunnions and pick up the vesselis mounted in a swivelable manner on the rear end of the loading part.The swiveling frame is moved by a hydraulic cylinder which occupiesdifferent positions for picking up, emptying and depositing the vessel.

[0003] A jib base which can telescope out hydraulically and which can besupported on the ground when the vessel is lifted or emptied by theswiveling frame is arranged at the end of the vehicle so that thevehicle is not subject to impermissible tilting moments or loadingmoments for the undercarriage as a result of the slag vessel to beswiveled over the rear. Further safety devices are not disclosed.

[0004] Road vehicles by which rubbish receptacles, for example, can bepicked up and placed on a platform of the vehicle, likewise with a rearswiveling device, are known from practice. However, vehicles of thistype generally have different emptying devices than those shown in DE 3605 665 C2. In order that the vehicles can pick up the receptacles by thetrunnions or the like stops, these load carriers must be standardized sothat gripping devices can always find their target at the same position.

[0005] Although the empty (tare) weight is usually written on thereceptacle, only the driver can estimate for himself whether or not thecontainer is too heavy for the transport vehicle. This results inoverloading of the vehicle beyond the permissible working load and alsoin a problem for the stability of the vehicle when lifting thereceptacle.

[0006] Therefore, the problem addressed by the invention is to increasethe safety of load transporters of the type mentioned above and to givethe driver information about the working load or safety hazards whichmight possibly occur. Overloading of or hazardous work with the loadvehicle must also be eliminated.

[0007] According to the invention, this object is met by the features ofclaims 1 and 10. Further developments of the invention are indicated inthe subclaims.

[0008] The invention is based on the idea that work with heavy-dutytransporters can lead to serious accidents as a result of carelessnesson the part of the operator and that, therefore, the driver should begiven information in every case about the working load to be handled forall working positions and loading work and, in every instance, incorrectoperation based on erroneous appraisal of the situation should beprevented by appropriate automated functions of the vehicle.

[0009] For this purpose, according to the invention, at least one of thehydraulic cylinders of the gripping device, preferably the hydrauliccylinder used as swiveling cylinder for the gripping device, is providedwith switches, at least one of which engages a pressure detection devicefor the hydraulic pressure in the cylinder on one or both sides of thepiston at a predefinable stroke of the piston, and the pressuredetection device switches on a safety device when a reference value forthe pressure which can be preset is exceeded.

[0010] The safety device can be an optical or acoustic signaltransmitter for the driver or can also comprise a plain text display orindicator which, in addition, also lights up in color.

[0011] In addition, the safety device should comprise a supporting basefor the vehicle frame, which safety device, when engaged, activates thesupporting base depending on a signal from the pressure detectiondevice. This need not be carried out automatically, but rather can alsobe triggered manually by the driver. Naturally, a mechanical supportingbase can also be swiveled in by the driver based on the indicator. Inthis case, however, the driver would have to cancel the acoustic oroptical indicator before setting the vehicle in operation after ensuringthat the supporting base is also in position.

[0012] The switches at the hydraulic cylinder are constructed asnoncontacting or contacting limit switches or the like and are coupledwith a device which likewise carries out a movement or which can beappropriately switched at a stroke of the piston of the cylinder,wherein the limit switch engages after a predefinable piston stroke andthe pressure monitoring means in the cylinder are accordingly switchedon. The device can act as a rod which is movable parallel to the strokeor as another kind of actuation device, e.g., one which also actscorresponding to the stroke, e.g., an inductive displacement pickup withor without mechanical, fluid or electric signal generation andtransmission.

[0013] The pressure detection devices in the cylinder can also beconstructed as simple pressure switches and, in this case, arepreferably arranged in the pressure line to the piston face side orpiston ring face side. An arrangement of this kind makes it possible tomonitor the pressure switches.

[0014] Instead of a simple pressure switch, the pressure detectiondevice can also be provided with means for generating a signalcorresponding to, preferably proportional to, the pressure, wherein thissignal can be used multiple times. On the one hand, a plain text displaycan be supplied to the driver in order to provide the driver withinformation about the working load that the driver currently desires tomove, or a scale or weighing device which, if required, may beelectronically controlled and also configured in recording mode isstarted so that the driver can document the transported loads at thesame time. When standardized load carriers, for example, buckets ormandrels which can pick up paper rolls or steel rolls, are used for thispurpose, the weight of these load carriers can be accounted for at thesame time and subtracted as tare weight from the load to be picked up inorder to arrive at the working load.

[0015] Naturally, it is important, especially for road transport, thatthe driver knows what working load he is transporting so as not toexceed the permissible vehicle weights, for example, on bridges.

[0016] In the event that the pressure detection device is onlyconstructed as a pressure switch, a pressure switch of this type can beused to block the movement elements or the hydraulic system of thevehicle, or the vehicle can be halted in general. In such cases, theblocking means would have to be connected with a key-operated switch inorder to allow the driver to set the vehicle in motion again after anappropriate correction of the load to be picked up or to operate thedevice within certain limits up to a predetermined reference value,which might often be necessary for emergencies.

[0017] Insofar as the heavy-duty vehicle is to be used, for example, asa device similar to a slag transporter, gripping devices acting inparallel on both sides of the heavy-duty vehicle with a correspondingrear swiveling device for buckets or the like load carriers are usuallyused. In order to prevent one-sided loading, the hydraulic cylinderscould be provided with corresponding pressure detection devices and/orlimit switches on both sides. This may only be necessary if noprecautions have been taken by means of appropriate simultaneous-runningor synchronizing elements such as connectors for the gripper devicesmounted at both sides or corresponding torsion elements which distributethe load over the vehicle.

[0018] The vehicle according to the invention can be used in particularas a slag transport vehicle for picking up slag buckets on a loadingplatform, since handling of hot slag is hazardous and the suggestedtipping-prevention devices substantially prevent incorrect operation.

[0019] The invention will be described more fully with reference toschematic drawings.

[0020]FIG. 1 shows the vehicle according to the invention in the readyposition for picking up a standardized load carrier, in this case a slagbucket;

[0021]FIG. 2 shows an enlarged schematic view of a hydraulic cylinderwhich is used as a tilting cylinder;

[0022]FIG. 3 shows the cylinder according to FIG. 2 in section withadditional elements;

[0023]FIG. 4 shows a loaded heavy-duty vehicle;

[0024]FIG. 5 shows a section of the vehicle with a slag bucket accordingto FIG. 4, but in emptying positions of the tilting cylinder and bucket;

[0025]FIG. 6 shows a depositing position for depositing a slag bucketaccording to FIG. 4 with corresponding positioning of the hydrauliccylinder.

[0026] Hereinafter, identical parts or parts having identical functionare provided with identical reference numbers.

[0027] First, the functioning of the overall device and of severalindividual parts in combination will be described, followed by a fewimportant details.

[0028] The vehicle according to FIGS. 1 and 4 essentially comprises thedriving head 3 and the load part 4. It is intended especially fortransporting liquid material such as liquid slag or molten steel inmetallurgical plants and steel mills and is oriented toward the adverseconditions of use prevailing in such plants.

[0029] The load part is connected with the driving head by abending-pendulum bearing 5. The tilting device 6 for the slag bucket 7is located on the load part. The slag bucket is used herein synonymouslywith other similarly standardized load carriers. Other load carrierscould be handled in the same way with the vehicle.

[0030] The slag bucket 7 is picked up from the ground by the hydraulictilting device 6. Instead of being level with the ground, the slagvessel could also stand on a platform or in a depression relative to thelevel of the road on which the load vehicle is driving. Naturally, thisresults in different leverages in the hydraulic tipping system and inthe hydraulic cylinder itself because the centers of gravity differ fromone another and the lever ratios vary.

[0031] In order to pick up the bucket, the vehicle drives backwardtoward the bucket with lowered tilting device 6, as is shown in FIG. 1,and lifts the bucket with the tilting device. As soon as the tiltingdevice has been moved in completely (FIG. 4), the slag bucket can belocked and then emptied by moving out the tilting device (FIG. 5). Afterthe bucket has been emptied, it can be turned completely around with thetilting device and deposited on the ground (FIG. 6) or, after beingfilled again according to FIG. 1, can be placed on the ground or in theoriginal position on the vehicle.

[0032] The tilting device 6 is a welded steel construction comprisingtwo tilting arms 9 (FIG. 1) which are connected with one another by astable torsion pipe 10 transverse to the vehicle. The torsion pipe inthis case ensures the synchronous running of the tilting arms on bothsides.

[0033] The tilting arms 9 are mounted at the rear of the vehicle and aremoved in and out by the main tilting cylinder 11. The tilting device isactuated by a master switch in the driver's cabin.

[0034] In order to pick up the slag bucket, the vehicle drives backwardtoward the slag bucket with the tilting arms extended as illustrated inFIG. 1 and picks up the bucket trunnion 12 with the claw 13 of thetilting arm. The slag bucket is lifted onto the platform 14 by theinward movement of the tilting cylinders. As soon as the slag bucket isin the driving position (FIG. 4), it can be locked by means of the sidelocking cylinder 15. Only after this has been carried out is the vehicleready to empty the slag bucket by means of the outward movement of thetilting cylinders (FIG. 5). This is carried out in particular by anadditional tilting device 16 which enables a tilting angle of up to 180°(FIG. 6). The slag bucket can be completely emptied in this way, ofcourse. This additional tilting device itself comprises two hydrauliccylinders which are accommodated in the tilting arms. In this case,again, a transverse pipe 17 ensures the synchronous running of thecylinders on both sides of the vessel.

[0035] Since the loading of the tilting system can fluctuate sharplydepending on the pickup height, namely, the ground or a depression or aplatform, the slag transporter is outfitted with overload-protectionmeans. This prevents the picking up of an impermissibly large weight oran impermissibly large torque. The overload protection can be adapted tothe different pickup positions and, naturally, also to the differenttypes of load carriers or other operating conditions.

[0036] The overload-protection means essentially comprise two limitswitches 1 a, 1 b which are in an operative connection with two pressuredetection devices 22, 23 according to FIG. 3. The limit switches arepositioned at the tilting cylinder in such a way that they are engagedat a given stroke of the cylinder.

[0037] If the driver wants to move the full slag bucket into thevehicle, it is necessary for safety reasons to know whether or not themaximum working load prescribed by the vehicle manufacturer is exceeded.In the initial position according to FIG. 1, the moved out cylinder 11has released a limit switch 1 b and accordingly triggered a signal formeasuring the pressure in the tilting cylinder ring face space 8 (FIG.3). The triggering of the signal for measuring is accordingly associatedwith a determined position of the tilting cylinder 11 and a determinedposition of the tilting arm and with a determined position of the slagbucket. In these positions, which are to be determined in advance andwhich are known on-site in the plant, the pressure in the tiltingcylinder ring face space 8 and the moments exerted by the constructionmasses and working load are in a defined relationship relative to oneanother, i.e., the actual working load can be determined, if required,added to the receptacle weight or added to the weight of the other loadcarrier. These values which are determined in this way can be processedas input values in electronics accommodated in the vehicle and canconsequently provide the driver with information about the working load,as such, or about a possible exceeding of the permissible working load.Optical, acoustic or plain text signals are used for this purpose.Further, the work hydraulics or the hydraulic system or electroniccomponents thereof can be acted upon by a signal, so that they are putout of operation. In certain cases, however, it is useful when thedriver can override this safety lock by means of a key-operated switchby his own initiative within certain limits.

[0038] At the same time, a weighing device or scale can be actuated in amanner not shown by means of these pressure detection means in order todocument the working load that is actually transported.

[0039] Alternatively or in addition to this information about theworking load, the system is also used for monitoring the pickup processfor picking up the full slag bucket. In this case, it must be ensured byadditional means that the vehicle has the required stability. In case ofoperating errors or failure to observe rules pertaining to dimensions,it may happen that the vehicle tilts about the rear axle 29 when pickingup a full slag bucket and the vehicle frame 30 (FIG. 1) is loaded to animpermissible degree, which again constitutes a considerable safety riskfor the driver.

[0040] In order to prevent incorrect operation, the warning signaldescribed above is configured in such a way that the driver is alertedabout his incorrect operation or further operation of the vehicle isblocked. The driver then has the possibility of manually mounting asupporting device 28 at the rear side of the vehicle or setting anexisting supporting device in operation. Naturally, when the signals arecoupled by the pressure detection devices in a corresponding manner, thesupporting device can also be put into operation automatically, so thatthe loading process proceeds faster and an incorrect arrangement of thesupporting device, for example, a hydraulic supporting base under thevehicle frame behind the wheel axle, is ruled out. The pressure levelfor the pressure detection devices, for example, simple pressureswitches, is advisably selected so as to be high enough to enablecertain work below this level without a supporting base being moved out,for example, the handling of an empty slag bucket (FIG. 6), but withoutjeopardizing the required stability when moving the empty bucket.

[0041] The measurement points or arrangement points for the limitswitches at the hydraulic cylinder and also the arrangement of thepressure detection device on the piston rod side should be identical forthese purposes in the arrangement shown in the drawings. This systemaccordingly has the function of informing about the permissible ormaximum working load and also has the function of preventing anoverloading of the vehicle when picking up full slag buckets or the likestandardized load carriers.

[0042] It is necessary when emptying the full slag bucket 7, or beforedepositing the full slag bucket, to set the supporting device 28 inoperation because stability could also be impaired in these movementprocesses and the vehicle could tilt or be impermissibly loaded alsowhen picking up the slag bucket.

[0043] In order to prevent incorrect operation of this kind, a pressuredetection device 22 is also mounted on the tilting cylinder piston side26, so that there is also information abut the pressure ratios in thesystem when movements of the type mentioned above are carried out. Forthis purpose, the corresponding vehicle geometry and stroke position ofthe cylinder 11 (FIG. 1) are again taken into account and, in this case,the pressure detection device is put into operation via the limit switch1 a (FIG. 2).

[0044] The optical or acoustic warning system mentioned above can beused in a similar manner with alternative signals to alert the driver ofpossible incorrect operation in these cases.

[0045] The functions of the vehicle in principle can be readilydiscerned from the position for road travel in FIG. 4, the position forpicking up the slag bucket in FIG. 1, the emptying positions of the slagbucket in FIG. 5, and the possible upside-down depositing position ofthe empty slag receptacle shown in FIG. 6. Details of FIGS. 2 and 3 willbe described briefly hereinafter. The hydraulic cylinder or tiltingcylinder 11 is secured to the vehicle, in this case, the load part 4(FIG. 1), by the eye 11 a, while the cylinder eye 11 b is coupled to thetilting device 6 and the tilting arms 9. A pipe 21 is arranged inparallel orientation at the cylinder 11 by fastenings 20, wherein a rod18 which is coupled with the eye 11 b via a fastening 19 is mounted in adisplaceable manner in the interior of the pipe 21. Two limit switches 1a and 1 b are positioned at the cylinder for different movementfunctions, taking into account the respective moment or torque duringoperation, such that the limit switches 1 a and 1 b can detect the endof the rod 18 which is displaceable with the piston rod 27. The limitswitches generate a signal from detection of the rod end and accordinglyact upon the pressure detection devices 22, 23 (FIG. 3).

[0046]FIG. 3 shows a view of the cylinder according to FIG. 2 in sectionwith the pressure space 26 and the annular space 8 on the piston rodside. The pressure switches 22, 23 are coupled to the pressure spacesclose to the directional valve 24 via pressure lines 25 and 13,respectively. These pressure switches 22, 23 can be used not only assimple switches, but also, for example, as proportional signaltransmitters for a display or indicator proportional to the workingload. This display can also be part of a weighing device.

1. Heavy-duty vehicle with a gripping device for picking up and moving astandardized load carrier which can be actuated by hydraulic cylindersand tipping-prevention means for the vehicle which are in operationduring the movement of the load carrier, characterized in that at leastone of the hydraulic cylinders (11) is provided with switches (1), atleast one of which switches (1) engages a pressure detection device (22,23) for the hydraulic pressure in the cylinder on one or both sides (8,26) of the piston at a predefinable stroke of the piston, and thepressure detection device switches on a safety device when a referencevalue for the pressure which can be preset is exceeded.
 2. Heavy-dutyvehicle according to claim 1, characterized in that the safety device isan optical or acoustic signal transmitter.
 3. Heavy-duty vehicleaccording to claim 1 or 2, characterized in that the safety devicecomprises a supporting base (28) for the vehicle frame (30), whichsupporting base (28) can be moved into an operating position whenengaged.
 4. Heavy-duty vehicle according to one of the preceding claims,characterized in that the safety device comprises means for blocking thehydraulic system.
 5. Heavy-duty vehicle according to one of thepreceding claims, characterized in that the switch is constructed as alimit switch (1 a, 1 b) which can be engaged by an actuating device (18)which acts corresponding to the stroke of the piston rod (27). 6.Heavy-duty vehicle according to one of the preceding claims,characterized in that the pressure detection device (22, 23) isconstructed as a pressure switch and is arranged in a pressure line (13,25) leading to the respective side of the piston.
 7. Heavy-duty vehicleaccording to one of the preceding claims, characterized in that theblocking means can be actuated by means of key-operated switches. 8.Heavy-duty vehicle according to one of the preceding claims,characterized in that the pressure detection device is outfitted withmeans for generating a signal proportional to the pressure for aweighing device and is outfitted with a weighing device.
 9. Heavy-dutyvehicle according to one of the preceding claims, characterized in thatthe gripping device (6) comprises a rear swiveling device for buckets(7) or load carriers that can be grasped at stops (12) provided at twosides.
 10. Heavy-duty vehicle for transporting slag with a loadingplatform (14) for slag vessels (7), comprising tipping-prevention meansaccording to one of the preceding claims.